Review notes: My first impressions of the sound of the AKG K553 are based on direct comparisons to other headphones - the v-moda M100 and XS, the FAD Pandora VI and IV, the Beyerdynamic T1 and T90, the AKG K812 and K712, and notes that I've accumulated from many prior reviews. I'll describe how I relate to the K553 (i.e. my personal tastes and how I use the headphone) only after covering all of the objective issues.

I reviewed 2 previous AKG headphones (the K812 ~$1200 and the K712 ~$350), and where the K712 was a good performer out of the box, the K812 needed significant EQ to have a proper tonality. Those 2 headphones enjoyed price reductions after awhile, but given the $120 price I paid for this K553 via Massdrop recently, I don't expect any further price reductions for this headphone. But that's not a negative, since the K553 is very well made and sounds great, and the value is excellent in the $100-plus price tier - "street price", that is. If you check the chart linked above or on my dalethorn website under Photos and Audioforge, you'll see that the response I measured (actually, EQ'd) is plus 2 to minus 3 db, or about as flat as you get with even the better headphones. The only significant coloration I found is in the bass, which isn't especially tight and detailed. For the price it's a nit-pick, and overall it sounds pretty good to me. Given a choice, I'd rather have a bass like this than a thin bass.

The K553 is a closed-back headphone, with better-than-average isolation and extremely low leakage, which should work well in most public libraries or very quiet offices. I've included 25 music tracks below that I used to test the different sound qualities of the K553, but I want to make a special mention of a new SACD I got in the post a few days ago - Anton Bruckner, Symphony No.8, Remy Ballot and the Upper Austrian Youth Symphony Orchestra. The recorded quality is fantastic on my better/pricier headphones and amps, but the K553 performs like the best of them on this music, which should be terrific news for potential customers - of the K553 and this SACD. Certainly most closed-back designs provide a less spacious sound than open-back headphones, on average anyway, yet the K553 is very good in that respect, due no doubt to having a full-up (but not bright) treble. Headphones that have a full, smooth treble with complementary mids and bass - they tend to have the best quality soundstage.

The K553 is a full-size headphone with really large earcups, yet the earpad openings are only 2.1 inches in diameter - large enough to go around my average size ears pretty well, but for users with larger ears, maybe not. The weight seems slightly heavier than average for its size, but it distributes well and is very comfortable, for me at least. For users who are bothered by even moderate headband pressure, I'd suggest moving the earcups down an extra 1/4 inch to carry more of the headphone weight with the earpads. For portability, the K553 can be pulled off the head when not in use, earcups folded flat, and worn around the neck with no discomfort. There is no carry case supplied - just a 3.5 mm to 6.35 mm (1/4 inch) adapter. The total range of adjustment is 1.5 inches on each side, 1/2 inch smaller and one inch larger than my average size head. The cable is single-entry, non-detachable, 10 ft long, terminated with a generic miniplug that's threaded for the screw-on 1/4 inch adapter.

My final judgement of the sound is that the K553 can be played without any EQ or tone controls for a full-fidelity experience, given only the bass caveat noted above. The soundstage is among the best I've experienced with a closed-back headphone, and I'd guess the 50 mm drivers make for a lot of that difference. In previous reviews I've included the following music examples with comments about how the headphones sound with each track. My suggestion is instead of reading each one as an absolute unto itself, you could compare my notes here to those other reviews and see how the K553 compares with each individual track. The comments below apply to using the K553 with the sources noted above, playing 44 to 96 khz WAV tracks, with no EQ or tone controls enabled.

Animotion - Obsession (1980's New Wave/Techno): The upper bass synth has excellent detail and tone, and both male and female vocals sound natural without favoring either. The K553 plays this extremely well.

Bauhaus - Bela Lugosi's Dead (~1980): Strong midrange sound effects - this is a good worst-case test for resonant-type sounds in the most sensitive midrange area. Handled perfectly by the K553.

Beethoven Symphony 9, Solti/CSO (1972): Excellent overall sound. Of special note here are the bass impacts beginning around 10:30 of the fourth movement. Those impacts are soft and well in the background, but you can really feel the weight they carry with the K553.

Black Sabbath - Iron Man (Classic Rock): Very good instrumental detail and the vocal sounds very natural. As with most classic rock tracks, there is very little or no deep bass. The K553 plays this music very smoothly, and the lack of deep bass doesn't unbalance the treble.

Boz Scaggs - Lowdown (1976): Great sound quality - this is a good test for any nasality in the midrange. Handled perfectly by the K553.

Cath Carroll - Moves Like You (1980's New Wave/Techno): This track's percussion and voice are crisp and well-balanced, and there's a good sense of space or soundstage around the voices and instruments. The K553 reproduces the space and detail extremely well.

Catherine Wheel - Black Metallic (~1991): Goth with industrial overtones - I like this since it's a great music composition and the sound effects are smoothly integrated into the mix. This may sound distorted or mushy with some headphones, but the K553 renders the deliberate instrumental distortions clearly.

Chris Isaak - Wicked Game (Pop/Rock): The K553 plays this high treble energy recording very smoothly - the voice and instruments are very detailed but not edgy - amazingly musical in fact.

Chromatics - I'm On Fire (Synth-Pop, female lead): This track has a good amount of space around the voice and instruments, making for a very pleasant stereo image. The voice is excellent, and the tambourine sound is realistic.

David Hazeltine - Fur Elise (Jazz): A very high-quality recording from HDTracks. The K553 reproduces the instruments smoothly with a spacious ambiance. The wire-brush-on-cymbal harmonics are very extended and detailed.

Ed Palermo - Crazy (Pop Vocal): A dose of big band, pop, country, and jazz with a unique vocal is Ed Palermo's Big Band, and this track is a great demo for the K553 - for instrumental tone and ambiance, and a perfectly-recorded vocal. The saxophone lead at 2:51 is especially gratifying.

Grieg (Beecham-Royal Philharmonic) - Peer Gynt-Solveig's Lullaby (Classical): This very old (late 1950's) stereo recording must have been made on the most expensive gear in the world, since the overall sound quality and especially Ilse Hollweg's amazing voice are as close to "being there" as I've heard with some of the better classical recordings made since the year 2000. The K553 plays this music perfectly.

Hans Zimmer - Dark Knight-Aggressive Expansion (Soundtrack): The percussion in this track hits really hard, and the bass tones beginning around 0:45 have the ultra-deep "shuddery" kind of sound that indicates a solid deep-bass response. Overall, the K553 plays this music very well.

Hugo Audiophile - 15-16 (Electronic): I'm not sure what the 15-16 stands for - perhaps track numbers from a CD album. The deep-bass tones that start around 33-34 seconds into the track reproduce extremely well with the K553. This is a great recording for evaluating whether a headphone's bass will be sufficient for most environments, since for many headphones that have a weaker bass, the deep bass gets absorbed and mostly lost when the environment contains a lot of low-frequency energy.

Jimmy Smith - Basin Street Blues (early 60's): This track has several loud crescendos of brass and other instruments that don't sound clean and musical with some headphones. The K553 reproduction is as perfect as I've heard. Listen particularly to the second crescendo at 15 seconds in for maximum detail. I want to emphasize that these crescendos are probably the worst-case test I have for instrument separation and detail, and the K553 does these exceptionally well.

Kellogg Auditorium, Battle Creek Michigan, Aeolian-Skinner Organ (1933) - Pedal, 32', Resultant, Arpeggio: This 16 hz organ pedal tone differs from other music tones in that you won't "hear" the tone - you'll only feel it. Although most music tones have harmonics (including this one), the harmonics from this tone will be too weak to provide any "feel", so whatever you actually hear would not be part of the fundamental 16 hz tone. There are ~30 hz sounds in the outdoor environment in big cities, generated by large trucks, buses, and subway trains, and they have a quality of "rumble" that's similar to some deep-bass tones found in music. This 16 hz organ tone is easily distinguished from those sounds when compared on a headphone that has good undistorted response at 16 hz. The K553 plays this with full weight and enough detail that you can hear/feel the 16 cycle per second analog "beats" of the fundamental tone.

Mantovani - Sunrise Sunset (Easy Listening, ca. 1972): A master musician and conductor** who specialized in light classics and orchestral pop music, Mantovani's accomplishments were overshadowed by music critics who couldn't tolerate the notion of "light classics" or "semi-classical" music, even when those recordings were no threat to the classical music genres. In any case the later Mantovani recordings from the mid-1960's through mid-1970's had the advantage of being mixed for much better hi-fi systems than those which the music critics possessed at the start of the Long Playing (LP) record cycle. Here in 2015, at least some of those digital remasters have improved the sound further, although it's not always the case. This track as played on the K553 is a perfect example of the sheer musicality lurking in those later recordings, and is highly recommended for soundstage, instrumental tone, and musical balance.

**Mantovani developed the "Cascading Strings" sonic effect circa 1950, a famous "Wall of Sound" effect for mono hi-fi systems that predated Phil Spector's own famous Wall of Sound effect by 10 years or so.

Michael Buble - Nice 'n Easy (Jazz): The voice is prominent but well-recorded, the massed instruments are delineated nicely, and the bass line especially is clear and detailed. This sounds pretty good with most headphones, but it's a special treat with the K553.

Michael Tilson Thomas - Rhapsody In Blue (20th Century Classic): Great sound and soundstage, and terrific piano playing and tone. There are some very deep bass impacts starting around 38 seconds into the 17:24 length track, and the weight of those impacts is impressive with the K553.

Pinback - Non Photo Blue (Pop-Rock): Crispy sound with "crunchy guitars and bashing drums" - the K553 renders this music as perfectly as I've heard an energetic pop-rock recording played with any headphone.

Porcupine Tree - Trains (Pop-Rock): This track opens with some nicely-detailed string sounds and a forward-sounding male voice with a higher-than-average register. There are a series of "clip-clop" effects starting at 3:19 that should sound like they were made with wooden blocks of some kind. The K553 reproduces the 'clop' portion of that sound fairly well.

Richard Strauss (Mester-Pasadena) - Also Sprach Zarathustra (opening) (Classical): The granddaddy of bass is in the opening 1:50 of this recording, and I've heard it only once on a large and expensive loudspeaker system in Cleveland. For most people, that experience would be indistinguishable from being in a fairly strong earthquake. The K553 conveys as much of that experience as is possible on headphones. The tympani also have excellent impact here.

Scarlatti-Kipnis - Sonata in E Major K381 (Classical, Harpsichord): The harpsichord here is fairly bright and highly detailed, and the K553 renders the tones and transients clearly.

Tiger Okoshi - Bootsman's Little House (Jazz): The trumpet here is recorded fairly close up and is somewhat bright with a significant "bite". The K553's reproduction is near-perfect, and the close-miked piano is also a treat. For comparison, I have several Maynard Ferguson tracks that feature a similarly strong trumpet with lots of brassy bite.

Trombone Shorty - Backatown (Jazz-Funk): The deep-bass impacts here are strong and work extremely well with the horns and other instruments. The K553 delivers the impacts with good weight and detail, and the horns have the kind of bite that gives them a wonderfully realistic sound.

As far as an enjoyable listen is concerned the 553's are more enjoyable and fun. The AKG 712's are boring but oh so clear and neutral. I returned my 712's because I couldn't justify the price ($452 w/tax) considering the 553's terrific performance, fun factor, and fantastic Massdrop.com price.

I also sold my Audio Technica ATH-M50x headphones once I got the AKG 553's too. They just couldn't cut it once I heard the 553's.